This invention relates to a rotating electrical machine and more particularly to an improved core lamination arrangement for such machines.
It has been known in rotating electrical machines to employ a core arrangement that has a core ring from which a plurality of core pole teeth radially extends. Conventionally, these cores are made from laminated ferromagnetic material sheets. Some arrangement is normally provided for insuring that the individual sheets of the lamination maintain their alignment.
Normally this is done by placing one or more indentations in the ring portion of the core. These indentations form a depression in one side and a complimentary projection on the other side. The projection of one sheet enters into the depression on the adjacent sheet so as to maintain the sheets in alignment. Normally the shape of these projections is that of a conical shape having a V configuration. Because of this configuration, it has been necessary to position the indentations in the ring part between its inner and outer peripheral edges.
A disadvantage with that type of construction is that the indentations form a disturbance in the flux field and the magnetic resistance increases. This deteriorates the magnetic properties of the core.
It is, therefore, a principal object to this invention to provide an improved arrangement for maintaining the positioning of the laminations of a rotating machine core without interfering with the flux characteristics thereof.
This invention is adapted to be embodied in a laminated core for a rotary electric machine. The core comprises a plurality of stacked lamination sheets formed from an electromagnetic material. Each of the lamination sheets is comprised of a circular core portion from which a plurality of circumferentially spaced pole teeth extends to receive coil windings. The peripheral edge of the circular core portion spaced from said pole teeth is formed with an indented portion forming a peripheral projection on one side thereof and a peripheral recess on the other side thereof. The peripheral projection of each of the lamination sheets is received in the peripheral recess of the adjacent of the lamination sheets for interlocking the lamination sheets.
In accordance with one embodiment, a single indented portion is formed around the entire peripheral edge of the circular core portion of each of the lamination sheets.
In accordance with another embodiment, a plurality of circumferentially spaced indented portions are formed around the peripheral edge of the circular core portion of each of the lamination sheets.